Boxes for packaging products of various kinds are commercially widespread which are traditionally constituted by parallelepipeds made of a material such as cardboard and are provided, at the two end faces, with closure flaps and tabs which mutually interlock.
Automatic machines which insert products in such boxes currently comprise at least one station where the flaps and tabs are closed after the product to be packaged has been inserted in the box.
These stations usually comprise closure elements which are operated by crank systems arranged at the two sides of the advancement line of said boxes; the motion of said crank systems defines a path which is suitable to guide the flaps, which are open and extended, in the direction for closure, making them interlock with the tabs provided at the end faces.
Currently, the use of these closure elements is rather disadvantageous for two main reasons.
First of all, such elements comprise oscillating masses whose high inertia limits the speed at which they can be operated, mainly due to problems linked to the transmission of vibrations which can become intolerable: this evidently makes it impossible to achieve the ever-increasing production rates currently required by the market.
Secondly, said closure elements comprise parts which are specifically intended for direct contact with the product and are sized according to the format of each box that the machine can fill: these parts must of course be adjusted whenever the dimensions of the box change. This need forces to stop production for periods of time currently considered too long in order to perform the adjustments.